1. Field of the Invention
The present invention relates to a method for manufacturing semiconductor devices which have penetration electrodes extending from a circuit forming plane on a surface of a substrate proper or main body to a rear surface thereof, and it also relates to electronic equipment incorporating therein semiconductor devices manufactured by such a method.
2. Description of the Related Art
FIG. 63A through FIG. 63G are cross sectional views showing respective process steps for manufacturing known semiconductor devices having penetration electrodes.
Hereinafter, reference will be made to the manufacturing procedure of the semiconductor devices while referring to these figures.
First of all, a substrate main body or proper 201 is produced which has a plurality of circuit element parts 202 with prescribed functions arranged on a circuit forming plane on one or obverse surface thereof, as shown in FIG. 63A.
Then, a plurality of holes 203 with a depth of 100 μm or less from the obverse surface of the substrate proper 201 comprising a silicon wafer are formed, as shown in FIG. 63B.
Thereafter, an insulating film is formed on the inner wall surface of each of the holes 203, and a metal film, which later becomes a cathode for electroplating, is then deposited on the insulating film. After that, with the metal film being made as a cathode, the interior of each of the holes 203 is buried or filled with a metal to form a penetration electrode 204, as shown in FIG. 63C.
Subsequently, the rear surface of the substrate proper 201 is removed until an end face of each penetration electrode 204 is exposed, as shown in FIG. 63D, and the rear surface of the substrate proper 201 is then selectively etched, as shown in FIG. 63E.
Thereafter, an insulating film 205 made of SiO2 is deposited on the rear surface of the substrate proper 201 by a chemical vapor deposition method (CVD), as shown in FIG. 63F.
Then, by removing the portions of the insulating film 205 covering the penetration electrodes 204 through etching by the use of a photolithography process, a semiconductor device assembly with the penetration electrodes 204 penetrating through the substrate proper 201 is produced, as shown in FIG. 63G, and it is finally divided into a plurality of pieces to produce semiconductor devices.
In the method for manufacturing semiconductor devices having the penetration electrodes 204 as constructed above, the etching process is performed prior to the formation of the penetration electrodes. In the case of using the etching process in this manner, however, the maximum depth of the holes 203, which can be formed by a trench etching process, is about 100 μm. Therefore, when the rear surface of the substrate proper 201 is removed until one end face of each penetration electrode 204 is exposed, the thickness of the substrate proper 201 cannot help being made extremely thin, as shown in FIG. 63D.
The post processing after this state includes an etching process step for etching the rear surface of the substrate proper 201, a process step for forming the insulating film 205 after the etching process, an etching removing process step for removing those portions of the insulating film 205 which cover the penetration electrodes 204 by means of photolithography, as shown in FIG. 63E through FIG. 63G. As a result, there arises a problem that the substrate proper 201, which has been made extremely thin, might be damaged by handling in these process steps, thus reducing the product yield of semiconductor devices.